Method of treating carbon articles of low initial conductivity.



LE SPRAGUE @L A. N'. fI'LLMf.f0l\,

ING CARBON ARTICLES o? Low lNITIAL CONDUGw-Yx lAPPLIGAI'ION FILED MAR.20,1912.

E. G. SPRAGUBST, A. M. WILLIAMSON. METHOD 0F TRBHING GARBQN ARTICLES 0F Low mm1, co-NDUCTWIT APPLICATION FILED MAR. 20, 1912. I 1,030,62Q. Patented June 25, MM2.

2 SHEETS-SHEET 2.

sierras Parana" orrroir EDMUNDC. SFRAG-Ull AND ARTHUR M. WILLIAMSON, OF NAGARA FALS, NEW YORK, ASSEGNOES 'C INTERNATIONAL ACHESGN GHRAlEHI'IEv COMPANY, 0F lAG-AR-.Pl

reims, New venir,

METHQD OF TREATNG GARBON .ARTI

.la CORPORATION OF NEW JERSEY.

CLES OF LOW INITIAL CONDUCTIVITY.

Specification of Letters Patent.

Patented J une 2541912..

To all when?, it muy concern.

Re it known that we, 'iE-namur C. SrnAGUE and An'rrrrn ."\l. lViLLrinsoN, citizens of the nUnited States. residing at Niagara Falls, in the county ol Kia@ Uri and State ot New York, have int euted certain new and useful improvements in lilethods of Treat-ing Carbon Articles of Lor.v initial Conductivity, of which the following is a specification.

This invention relates to the treatment of carbon articles, and especially to the treatment of unbnlred or green carbon electrodes or the like, for the purpose of increasing their electrical conductivity.

lduction of several vclasses of finished articles, depending upon the duration and other -conditions oit' heating, and upon the cha-racter ot the initial material; that is to say the carbon articles may be baked or polymerized to any desired degree,lor they may be g-raphitizcd.

According to the preferred embodiment of the invention, green or unbakedcarbon articles, of which the initial electrical conductivity is too low to permit them tobe .heated a commercially practicable manner by the passage ci' an electr'iocurrent through their mass, are charged or ar-v ranged in an electric piles or stacls which posed transversely to the current path, the several piles separated from each other in the direction oit current itlov by a subdivided or granular resistano'lematerial.. The articles are initially heated by means Aoi tivo or more resistance bodies laterally disposed with reference to the piles, and er-- 'tending between the heads cirterminals of the tur-nace. Thereafter, when the conductivity ot' the carbon articles has increased sufciently to permit such ett'ect, a part of the current lons through the piles of articles and through the interposed resistance material, resulting in a further heating of the articles by heat developed in such interposed material. Byproceeding in this manner, several important advantages are secured, as hereinafter pointed out.

For a full understanding o1 the invention reference is made to the accompanying drawings, diagrammatic in character, wherein- .rnace in theform of: are preferably dls- Figure 1t is a transverse vertical ,sectionof carbon,

.tized tin av series of piles 2, arranged transversely Ipile 2, are superpos'ed in:

` piles 2. are separated -from each other by 4fvarlations in certain portions of the furnace. during an illustrative furnace run;

Fig. et is a horizontal section of one end of a furnace provided with means for sepa- -rately jheating cores;` and Fig. 5 is a transverse vertical. section of adurnace having three l heating cores.

The invention is applicable for the lpro,` l

controlling the temperature of the 6 5 In said drawings, l, l indicates articles as for example green carbon electrodes which are to he baked or graphi- Said articles are shown as disposed -With respect to` the longest. dimension of the furnace and to the path of 'tween the terminal heads or electrodes 3, 4.1.

the current be- The several articles l, cbnstituting a single.y

contact withfeach 'v other or very slightly separated,v it being' y preferred to prevent such actual vcontact as might result in Welding the articles, to'

ether by. the use of thin layers or films of ne carbon or carbon dust. rlhe several layers 5 of granular conductive carbon, for' which purposeA coke, which has undergone heatingin -a'previous furnace operation and has been thereby rendered conductive, is Well suited. The end piles of the series are maintained in conductive relation with the inner endso'f the electrodes 3, l by granular layers of like material designated by the reference numeral 6.

7, 7 represent longitudinal cores ot granular or subdivided conductive material, preferably ot' the same character as that con" stituting the intermediate layers These cores are properly proportioned'with reerf ence to the current to be employed, to carry the greater portion dr all of the current during the earlier stages of the heating operation. B'represents an insulating mixture, as for example a mixture of coke and sand, which completely embeds or surrounds the articles to be heated` or converted, being preferably prevented from Vdirect contact therewith aboveI and lbelow the piles by carl bon beds 7E, 7'* of materially lowerv conclue web:

[9. The Inethod cintre-ting carbon articles o :t' low initial conductivity 1n iin-electricite* sistence furnace, v rfhichA consists in disposlng said articles in series of piles with interposed resistance material, electrlcally heating said piles chiefly from the opposite ends thereof until the articles;` are rendered elec- -tricelly conductive,"thereafter heating said piles throughout t-heinlength by heabde velope'd in said vinterposed resistance niatermi,l and independently controlling' the lapplication of heat to the respective ends Ofsaid piles.

l0. The method of tneat-ing carbon articles of low initial conductiiv'ity in an electric resistemate' furnace, whichI consists in disposing said articles in a series of piles with interposed resistance material, seid' piles arranged transverse to the current path, electrically heating said piles chiefly from the opposite ,vends thereof nntilthe articles are rendered electrically conduetiventhereafter heating ,il mennen said piles throughout their length .by heut developed .in said interposed resistance matei-inl, end independently controlling the application of heat to the'respective ends of said piles.

11. The method of treating carbon artixcles' of 10W initial conductivity in an electric resistance furnace, which consists in initially heating said articles chiefly from their opposite ends until they are rendered electrically conductive, thereafter heating them with substantial uniformity throughout their length, and independently controlling y the application of heet to the respective ends 

